1. Field of the Invention
The invention relates to a device for processing feedstock.
2. Description of the Background Art
Devices of this type belong to the field of mechanical process engineering, the goal of which is to process and transform source materials into a predetermined end product or intermediate product for further process steps. Possible types of processing and transformation are the different methods of mechanical crushing as well as agglomeration, mixing, separation, coating, drying, compacting and the like. The feedstock may vary in nature and largely involves substances from organic and anorganic chemistry, including dyes and pigments, the food and plastics industries as well as mineral substances. The range of applications for devices according to the definition of the species is correspondingly broad, these applications being adapted to the special characteristics of the feedstock, the desired end product and the type of processing through suitable selection of the processing tools and by maintaining preset process parameters.
To minimize investment in new machinery and machine components, it is desirable from the perspective of the operator of such devices to be able to perform as many types of processing as possible using a single device, in order to adapt to different feedstock and objectives. However, this requires the ability to retool a device, if necessary by exchanging the machine components characteristic for processing, between one application and a subsequent application, which should be done as easily and quickly as possible in the interest of economical operation.
Another aspect, which has to do with the ability to easily disassemble devices according to the definition of the species, lies in cleaning the device. In the chemical and pharmaceutical industries, in particular, great care must be taken when changing feedstock to avoid mixing the material previously processed with the material to be processed subsequently, which would compromise the material purity of the end or intermediate product. A similar consideration applies to the food industry, where a device according to the definition of the species must be completely and thoroughly cleaned after a standstill or change in feedstock for reasons of hygiene. It is therefore important to easily disassemble and reassemble devices according to the definition of the species, not only due to economic considerations, but also because this has a considerable influence on the quality of the end product.
A mill having multiple milling sections, in which a cylindrical housing coaxially surrounds a rotor, is known from EP 0 226 900. The housing is sealed on one side by a welded-on base structure having integrated material and air supply means. On the diametrically opposed side, a cover connected to the housing via a flange joint and threaded bolts forms the housing closure. The rotor drive shaft is run on bearings on both sides in the area of the base structure and the cover. The rotor has grinding plates which are distributed over its circumference and interact with a stator on the inner circumference of the cylindrical housing. It is possible to disassemble this device only to a limited extent and with considerable effort. Due to the effort involved, it is not economical to retool the device for changing feedstock, which means that devices of this type are used mainly for invariable feedstock and production conditions.
Another prior-art publication is DE 23 53 907 C3, which discloses an impact mill having a housing within which is disposed a rotor in the shape of a truncated cone, which has a plurality of grinding tools oriented in an approximately radial direction. The rotor drive shaft is run on bearings on only one side in the area of the base. The housing includes a central element in the shape of a hollow truncated cone, which forms a stator on the inside and is closed on the bottom by a base and on the top by a cover. The base and cover are connected via flange joints and threaded bolts, which are not illustrated in further detail. This mill has the advantage over the one described above in that both the cover and base are removable, which however is still associated with a considerable amount of work due to the presence of the flange joints.